General Cosgrove, who was speaking at a Liberal Party function in Melbourne, said the soldiers involved in the slurs should be counselled and reminded that the defence force did not condone intolerance.

Opposition Leader Tony Abbott said the comments should not have been made.

"I understand the military authorities are taking appropriate action against it."

Defence Minister Stephen Smith has personally apologised to his Afghan counterpart for offensive comments posted by some Australian soldiers on Facebook.

Mr Smith described as "appalling" the conduct of the small number of soldiers who now face disciplinary action and the prospect of being sent back to Australia.

"I apologised to him on behalf of Australia," he said of his call to Abdul Rahim Wardak.

"I made the point to him that the chief of the defence force and the chief of army were investigating this matter and in all likelihood disciplinary proceedings would follow.''

Mr Smith said Mr Wardak responded by saying that he did not believe the incident would diminish the standing of Australian troops in Afghanistan.

"He appreciated very much and respected very much the way that Australian soldiers conduct themselves," he said.

That conduct covered sticking to "sensible rules of engagement" and engaging with the local people.

And when things go wrong, "fessing up to them" and taking remedial action.

The army is investigating what it says is "totally unacceptable" behaviour.

Videos, broadcast on last night by the Seven Network, show soldiers referring to Afghans as "sand coons", "dune coons", "niggers" and "smelly locals".

Another is referred to as a "raghead''.

When a local man was shown running away from an explosion, a soldier was heard to say that the blast "scared the f--- out of that mufti".

A number of soldiers list their employer as a "f---ing ranga", a reference to Prime Minister Julia Gillard.

Mr Smith said such conduct was of the most appalling kind which brought the army into disrepute.

It also had the potential to bring Australia into disrepute.

Mr Smith said he was confident defence force chiefs would pursue the matter to the end.

That could include disciplinary action and returning anyone found responsible back to Australia.

"In advance of that investigation, it is open to a local commander, if he believes that, prima facie, conduct has occurred which would warrant action, he can take it on the ground," Mr Smith said.

But the brother of one former Victorian soldier said last night that his sibling was not a racist and he had joined the army to serve and protect.

"I have never found (him) to be a racist person," the brother said.

Acting Chief of Army Maj-Gen Paul Symon said the army was appalled. "I struggle to understand, with all the training that we do and with the quality of soldiers that we have, that that sort of language has been posted," he told Seven News.

"When you put words in the public domain, you will be held responsible," he said.

"What is happening here will cause deep offence to a lot of people."

One Facebooker wrote that he he had just done an interview with the army and was waiting for a place in cavalry.